Just to clarify - there is no current selection object in QlikSense. There is selection bar on top. Out of the box you cannot control properties of this object.
You can however define fields which when selected will not apear in selection bar. You can do it through few different methods like:
- tagging "hidden"
- using Hide Prefix variable
- using Hide Suffix variable
Those methods work both in QlikView and Qlik Sense. The drawback is that you have to specify fields which ALWAYS will be hidden.
From what you have written i assume that you always want only 3 first fields to be shown in your selection. That would be harder to achieve in QlikSense - I assume only though mashup object which then becomes more advanced.